power issue for Mega with tft touchscreen

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1

Hi everyone, my question could probably be a power related topics but the main issue is the TFT Touchscreen.

Some years ago a made a project with a Mega, a tft shield (2.0 I think) and a tft touch screen (sorry i don't have any model number). I enclosed everything in a small box with other component like an nrf24l01 and a rtc clock. It is powered from a 9v wall power directly in the mega's power jack.

Everything worked well for about 2 years. But with small kids, they have dropped this box several time on the floor. So for the last 2 month my tft touchscreen, is now acting strangly, i'll try to explain it briefly.

my project have a "main" screen and a "setting" screen. My main screen have two button (image encoded in my code) some text and a setting button in the bottom. Right now half of the main screen is displayed, but i can still touch where are the buttons and it work. when i go to my setting screen, everything is displayed. Going back to the main screen bring back the problem.

I tested other power adapter of many voltage, still having problems. BUT when i plugged it with my computer's usb, It worked well. So I checked the voltage from every place I can on the board, everything looks ok. BUT if a use a usb wall adapter to use usb as power supply, the problem is back again.

I don't understand what can be the problems, every power source isn't working except my cpu's usb.

i'm joinning an picture of what it look (with label to show different power source) (and don't care about the language of my project, i'm french from canada :slight_smile: )

if anybody have idea ?

NB: I tryied with another mega board and still the same problem

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20201015_205853.jpg
20201015_205853.jpg2896×2896 591 KB

2

If I understand this when you power via the USB it works fine but if you power using the Vin it gives you problems. I am just guessing but I am assuming the display is powered from the Arduino. It could be the regulator or capacitor on the Arduino board. This type of failure can cause high frequency oscillations that a volt meter will not pick up. If you can try another board give it a try. I can only guess at this point, sorry I cannot give you more help. A schematic would help.

3

Thanks.

Only usb from my computer work, a wall usb supply wont work. And another board is doing the same thing.

Maybe my tft shield is the problem because i tryed something yesterday night after sending my post. Seeing my setting screen was working fine and the fact there was no bitmap image in it, i decided to remove my main screen button's image to replace it with a simple "shape" button and now everything is working fine...

So it look like many drop on the floor cause some processing problems with bitmap image displaying... strange.